/*********************************************************************
 *                
 * Copyright (C) 2002-2005, 2007-2010,  Karlsruhe University
 *                
 * File path:     glue/v4-x86/timer-apic.cc
 * Description:   implementation of apic timer
 *                
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *                
 ********************************************************************/
#include INC_ARCH(trapgate.h)

#include INC_GLUE(idt.h)
#include INC_GLUE(intctrl.h)
#include INC_GLUE(timer.h)

#include INC_PLAT(rtc.h)

#include INC_API(schedule.h)

DECLARE_TRACEPOINT(X86_APIC_TIMER);

/* global instance of timer object */
timer_t timer UNIT("cpulocal");

static local_apic_t<APIC_MAPPINGS_START> local_apic;


extern "C" void timer_interrupt(void);
X86_EXCNO_ERRORCODE(timer_interrupt, 0)
{
    scheduler_t *scheduler = get_current_scheduler();
    
    //TRACEPOINT(X86_APIC_TIMER, "APIC TIMER %d", (word_t) scheduler->get_current_time());

    local_apic.EOI();

    /* handle the timer */
    scheduler->handle_timer_interrupt();
}   



void timer_t::init_global()
{
    TRACE_INIT("\tglobal timer: trap gate %d\n", IDT_LAPIC_TIMER);
    idt.add_gate(IDT_LAPIC_TIMER, idt_t::interrupt, timer_interrupt);

}

void timer_t::init_cpu(cpuid_t cpu)
{ 
    intctrl_t *intctrl = get_interrupt_ctrl();
    bool pmtimer = intctrl->has_pmtimer();
    
    // avoid competing for the RTC
    static DEFINE_SPINLOCK(timer_lock);


#if !defined(CONFIG_CPU_X86_SIMICS)
    TRACE_INIT("\tCalculating processor speed (CPU %d)...", cpu);
    local_apic.timer_set_divisor(1);
    local_apic.timer_setup(IDT_LAPIC_TIMER, false);
    local_apic.timer_set((u32_t) -1UL);


    word_t delay = 0;
    
    /* calculate processor speed */
    if (!pmtimer)
    {
        timer_lock.lock();
        delay = 1000;
        wait_for_second_tick();
    }

    u64_t cpu_cycles = x86_rdtsc();
    u32_t bus_cycles = local_apic.timer_get();
    
    if (pmtimer)
    {
        delay = 100;
        intctrl->pmtimer_wait(delay);
    }
    else
    {
        wait_for_second_tick();
        timer_lock.unlock();
    }

    word_t local_apic_cpu_mhz;
    word_t local_apic_bus_mhz;

    cpu_cycles = x86_rdtsc() - cpu_cycles;
    bus_cycles -= local_apic.timer_get();

    local_apic_cpu_mhz = cpu_cycles / (delay * 1000);
    local_apic_bus_mhz = bus_cycles / (delay * 1000);

    proc_freq = cpu_cycles / delay;
    bus_freq = bus_cycles / delay;
#else 
    /*
     * Set frequencies statically on SIMICS, waiting would take ages...
     */

    cpu_cycles = CONFIG_CPU_X86_SIMICS_SPEED * 1000 * 1000;
    proc_freq = cpu_cycles  / 1000;
    bus_freq = 0;

#endif 


    TRACE_INIT("\n\tspeed: %d MHz, bus speed: %d MHz (CPU %d)\n", 
               (word_t)(local_apic_cpu_mhz), local_apic_bus_mhz, cpu);

    /* now set timer IRQ to periodic timer */
    local_apic.timer_setup(IDT_LAPIC_TIMER, true);
    local_apic.timer_set( bus_cycles / (1000 * delay / TIMER_TICK_LENGTH) );

}